Fix for 3893 : dsreplication enable between 1.2 and 1.3 can fail because of Initialize task

A while ago, I moved the replication tasks to the replication package so that
all the replication code stay in the replication packages and to avoid
to make method public.
However it now appears that this break the compatibility of the 1.3 builds
with dsreplication fron older release.

This change therefore reverts previous change, moving back the replication
tasks to the tasks package.